You don't need to nor would you want to paint the gold stripe on CO's a/c. If you have a set of decals for it, it should have decals for the stripes on the sheet anyhow.
I do however think you meant the grey color for the lower half of the fuselage. For that use Testors Canadian Voodoo Grey(FS16515). Its an almost exact match for Boeing Grey which is what the wings and horizontal stabilizers on Boeing aircraft are painted. You will need an airbrush to apply it though because testors only makes it in bottle form. Your paint job will come out much better though.